The optically generated microwave oscillator with long-term stability locked at hydrogen maser
| Autor: | Shao-Yang Dai, Fang Fang, Kun Liu, Wei-Liang Chen, Nian-Feng Liu, Shi-Ying Cao, Tian-Chu Li |
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| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | AIP Advances, Vol 10, Iss 6, Pp 065118-065118-5 (2020) |
| Druh dokumentu: | article |
| ISSN: | 2158-3226 66080738 |
| DOI: | 10.1063/5.0003839 |
| Popis: | We present an oscillator of optically generated microwaves (OGMs) based on an optical frequency comb (OFC) and an ultrastable laser (USL). The USL provides short-term stability, and the OFC transfers the short-term stability to radio frequencies. Frequency synthesis is used to transfer the stability of the OGM oscillator to an oven-controlled crystal oscillator (OCXO). To improve the long-term stability of the OCXO, an additional compensating loop was applied to lock the long term stability of OGM at a hydrogen maser by compensating the frequency drift of the USL. The phase noise of the OCXO is maintained sufficiently low through these locked loops. The OCXO’s phase noise at 1 Hz is about −116 dBc/Hz. The short-term stability (1–100 s) of the OCXO with different compensating periods is better than 4 × 10−15. By replacing the H-maser (BIPM code: 1404850) with the OGM as the local oscillator, the stability of the NIM6 Cs fountain clock is improved from (1.2 × 10−13)τ−1/2 to (5.1 × 10−14)τ−1/2. This work should help optimize fountain clocks for better type A uncertainty or faster frequency offset evaluations. |
| Databáze: | Directory of Open Access Journals |
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